This invention relates to novel molds made of nickel shells by direct nickel vapour deposition and, more particularly, relates to molds made of nickel shells by nickel vapour deposition wherein said molds have steel parting line components and heating and cooling lines encapsulated within the nickel shells.
The production of nickel molds by the electrodeposition of nickel on cathodes of desired shapes is well known. Typical nickel shapes produced by electrodeposition do not have uniform thickness, particularly at right-angled joints, with the result that flanges, for example, are weak and often break. Electrodepositions are also prone to voids and residual stresses. In addition, the electrodeposition of nickel on a cathode to form a nickel shell of desired thickness normally takes an inordinately long time, resulting in low production rates with high expense.
The forming of nickel shells for molds by nickel vapour deposition on mandrels is known. Nickel vapour in the form of nickel carbonyl gas is passed over a heated mandrel in a deposition chamber and, as the nickel carbonyl gas contacts the hot mandrel surface, it decomposes to form a hard and dense nickel deposit. The deposited nickel as a layer accurately reproduces the surface details of the mandrel on which it is deposited. The nickel layer is uniformly deposited on the mandrel, regardless of shape, thereby producing adequate thickness in irregular shapes such as at sharp corners.
The nickel metal is deposited relatively quickly permitting the production of nickel shells with desired thickness in a relatively short period of time compared to electrodeposition.